The ability of a soil or other material to retain and exchange positively charged ions (cations) is quantified by a specific measurement. This measurement represents the total amount of exchangeable cations a material can hold, expressed as milliequivalents per 100 grams (meq/100g) or similar units. For example, a soil with a value of 15 meq/100g indicates it can hold 15 milliequivalents of cations for every 100 grams of soil.
This property is crucial for nutrient availability in soils, influencing the retention of essential plant nutrients such as calcium, magnesium, and potassium. A higher value generally indicates a greater capacity to retain nutrients and buffer against nutrient loss, contributing to soil fertility and plant health. Understanding this value also aids in predicting the behavior of contaminants in the environment, as it influences the adsorption and mobility of heavy metals and other positively charged pollutants.
